Democrats are struggling to hold a U.S. Senate seat and the governorship in Pennsylvania

Philadelphia, Pennsylvania (CNN) -- President Barack Obama defended his record on the economy, ripped into Republicans and implored weary Democratic voters to head to the polls next month in a campaign-style speech in Philadelphia, Pennsylvania, on Sunday.

"Are you fired up, are you ready to go?" Obama asked the crowd as he approached the podium Sunday afternoon, sounding very much like candidate Obama and invoking his 2008 victory repeatedly throughout his speech.

"Two years ago you defied the conventional wisdom in Washington," the president said. "They said, 'no you can't.' They said, 'no you can't overcome the cynicism of politics, no you can't overcome the special interests and the big money ... no you can't elect a skinny guy with a funny name to the presidency of the United States.'"

"And what did you say?" Obama asked supporters gathered outside Philadelphia's Robert Fulton Elementary School for what was officially a Democratic National Committee rally.

As if on cue, the crowd began chanting "Yes we can," a refrain from Obama's 2008 campaign stops.

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Obama's stop in Pennsylvania is one in a series of appearances he's making in states that he easily took in 2008 but where Democrats are struggling to hold onto U.S. Senate and House seats ahead of next month's midterm elections.

In Pennsylvania, Democratic Rep. Joe Sestak -- who spoke before Obama on Sunday -- is locked in a tight race with former Rep. Pat Toomey for the U.S. Senate seat being vacated by Democrat Arlen Specter.

Pennsylvania Reps. Patrick Murphy, Chris Carney and Paul Kanjorski -- all Democrats -- are at risk of losing their seats next month, political analysts say, while the governorship is up for grabs in an open-seat race.

As he urged Democratic voters to defy the conventional wisdom that they are apathetic going into the midterms, Obama sought to place his sweeping 2008 win in a broader historical arc.

"Our victory on that campaign, that wasn't the end of the road," he said. "That was just the beginning of the road."

Obama said that his administration had staved off a second Great Depression by making unpopular choices to bail out major American corporations.

"Twenty months later, we no longer face the possibility of a second Depression," he said. "Our economy is growing again. The private sector has created jobs nine months in a row."

"There are 3 million Americans who would not be working today if not for the economic plan me and Joe put into action," he said, referencing Vice President Joe Biden, who was seated behind him.

Obama blamed the Republicans for the economic crisis, comparing the administration's work on the economy to pushing a car out of a ditch.

"We're starting to make progress and suddenly we get a tap on our shoulders and we look back and who is it -- the Republicans, and they say 'We want the keys,'" the president said. "But Philadelphia, they can't have the keys back. They don't know how to drive."

After the rally, Pennsylvania Gov. Edward Rendell praised Obama's speech but said that Democrats need to do more to tout accomplishments from the past two years.

"It's very important for the president to talk to our base," Rendell told CNN's Don Lemon. "The turnout in the greater Philadelphia area will determine the statewide elections for sure."